一种基于MODIS影像反演太湖Ⅱ类水体上空气溶胶参数的算法

基于Ⅱ类水体短波红外（Short-Wave Infrared,SWIR）波段离水反射率为0的假设,提出一种反演Ⅱ类水体上空气溶胶参数的算法（CaseⅡWater Algorithm, C2W）,并与AERONET(Aerosol Robotic Network)太湖站实测数据进行了比较分析.结果表明,反演得到的0.670μm与0.870μm两个波段的气溶胶光学厚度（Aerosol Optical Depth, AOD）与实测值呈现明显的线性关系（R2=0.974、0.971）,在气溶胶光学厚度τ>0.2时不确定性在Δτ=±0.03±0.05τ范围内.11期气溶胶有效半径（Aerosol Effective Radius,AER）数据中,9期的不确定性在±25%范围内,另外两期数据的不确定性在±30%以内.反演精度符合MODIS气溶胶产品的精度要求.     

Distribution and sources of solvent extractable organic compounds in PM2:5 during 2007 Chinese Spring Festival in Beijing

The solvent extractable organic compounds (SEOC), including n-alkanes, polycylic aromatic hydrocarbons, fatty acids, anddicarboxylic acids in PM2.5 during the 2007 Chinese Spring Festival in Beijing, were measured via gas chromatography-massspectrometry for determining the characteristics and sources of these organic pollutants. The concentrations of total n-alkanes, PAHs,and organic acids before Chinese Spring Festival Eve (1025.5, 95.9, and 543.3 ng/m3, respectively) were higher than those after (536.6,58...     

用于模拟SOA形成的烟雾腔的构造和表征

为研究二次有机气溶胶的形成机理,设计制造了一种用于模拟二次有机气溶胶的形成过程烟雾腔实验系统,该系统主要包括样品进样系统,模拟反应系统即烟雾腔系统和产物检测系统三个部分,具有实时在线检测、效率高等优点。利用该实验装置模拟开展大气中含量较高的芳香烃化合物光氧化产生二次有机气溶胶的过程,使用TSI3321空气动力学直径测量系统、气溶胶飞行时间质谱等多种检测手段对二次有机气溶胶的形成进行表征。空白实验和羟基启动的光氧化实验结果表明烟雾腔内的气溶胶粒子是在黑光灯辐照下·OH自由基启动反应物光氧化产生的。实验结果表明研制的烟雾腔系统可以很好地实现对二次有机气溶胶形成过程的模拟和表征。     

Experimental study of photooxidation products of ethylbenzene

Smog chamber experiments were performed to investigate the composition of products formed from photooxidation of aromatic hydrocarbon ethylbenzene. Vacuum ultraviolet photoionization mass spectrometer and aerosol time-of-flight mass spectrometer were used to measure the products in the gas and particle phases in real-time. Experimental results demonstrated that ethylphenol, methylglyoxal, phenol, benzaldehyde, and 2-ethylfurane were the predominant photooxidation products in both the gas and particle phases. However, there were some di erences between detected gas phase products and those of particle phase, for example, 2-ethylfurane, ethylglyoxylic acid, nitroethylbenzene, 3,4-dioxopentanal and ethyl-nitrophenol were only existing in the particle-phase. The possible reaction mechanisms leading to these products were also discussed and proposed.     

新疆阿克达拉大气背景点气溶胶物质来源研究

文章利用2004年7月~2005年3月间新疆阿克达拉区域大气本底观测站PM10和TSP有机碳、元素碳及水溶性离子的组成数据,分别采用主成分分析法(Principal Component Analysis,PCA)和绝对主成分分析法(Absolutely Principal Component Analysis,APCA)对大气气溶胶物质来源进行研究。结果表明PM10中气溶胶来源及贡献率分别为:人为污染源(49.6%)、地壳矿物质粉尘(17.3%)、盐渍化地壳矿物质粉尘(33.1%);TSP中气溶胶来源及贡献率分别为:盐渍化地壳矿物质粉尘(21.3%)、地壳矿物质粉尘及人为污染混合源(50.8%)、人为污染源(27.8%)。由于阿克达拉大气本底观测站位于我国气候上游,该站PM10和TSP中不同来源物质贡献率的源解析结果对于研究中国西北地区大气背景气溶胶的特性及其气候效应具有重要意义,对我国西北边境大气背景区空气污染治理对策的制定有一定的参考价值。     

青岛大气气溶胶中无机氮组分的粒径分布特征

2005年7月～2006年8月对青岛大气气溶胶进行为期1a的连续观测,分析了气溶胶颗粒以及气溶胶中无机氮组分(NO2-N、NH4-N、NO3-N)的粒径分布。结果表明:颗粒物随粒径分布全年呈现明显的双峰分布,最高峰值出现于0.43～0.65μm的积聚模态,次峰值出现于3.3～4.7μm的粗模态,春季三月沙尘期间的粗模态峰值最为明显。NO3-N的分布略微复杂,夏、春季节与颗粒物类似呈现双峰分布,在粗粒态和细粒态上各出现峰值,而秋冬季节呈现单峰分布,最高峰值均出现在积聚模态;NO2-N性质不稳定,无明显的季节变化规律,但其全年平均却表现出一定的规律,呈现多模态分布;NH4-N的粒径分布的峰值均呈现单峰分布,峰值出现于0.43～0.65μm的积聚模态,无明显的季节变化。另外研究发现,春季沙尘天气和夏季海盐组分都对青岛大气气溶胶颗粒物及其中无机氮组分的粒径分布均有一定影响。     

绝对主因子分析法解析北京大气颗粒物中铅来源

2005-09-18～2006-09-13期间,在北京南郊房山区、城区西二环和北郊昌平区3个采样点采集了166个总悬浮颗粒物（TSP）样品.用ICP-AES和ICP-MS方法测量了铅等29个无机元素.南郊、城区、北郊3个站点大气铅浓度年平均值分别为179、 142和102 ng·m^-3.用绝对主因子分析法定性识别和定量解析了TSP样品中铅的来源.结果表明,北京TSP样品中铅的来源及分担率分别为：涉铅有色冶金工业（55.6%）、燃煤（16.9%）、建筑尘（11.8%）、土壤扬尘（10.2%）.涉铅有色冶金工业是主要来源.从空间分布看,燃煤、建筑尘、土壤扬尘等来源排放的铅分布比较均衡, 3个点位的浓度大体持平;来源于有色冶金工业的铅浓度年均值在3个站点从南到北,分别为113、 77.0和44.2 ng·m^-3,具有南高北低的趋势.这提示工业来源的主要方位在北京的南边.北京市大气铅浓度有可观的下降空间.铅排放削减和有关环境管理措施的主要对象应该是北京南边的有色冶金,特别是涉铅有色冶金行业.同一套化学组成数据计算结果显示,土壤扬尘和建筑尘是TSP的主要来源,分担率是72.3%.其他来源还有：燃煤（13.4%）,有色冶金工业源（9.5%）.     

液体气溶胶抑制受限空间内烃类挥发的实验研究

在含有残留油品的受限空间内作业时,易发生油气燃爆事故。利用两性离子型氟碳表面活性剂组分制备了具有低表面张力的抑爆剂溶液,能够在易挥发烃类液体表面自由铺展成液膜,从而对烃类液体形成液封,抑制油气挥发。利用超细雾化装置,能够将抑爆剂溶液雾化形成液体气溶胶,气力输送至受限空间内。实验验证了受限空间内液体气溶胶中的微小液滴能够沉积在残留油品的表面形成液封,同时液滴和液膜的气液界面能够吸收空间内的油气分子,从而降低空间内的油气浓度。研究证明,利用抑爆剂液体气溶胶混合物来置换含残留油品受限空间内的油气,能够将受限空间内的油气浓度长久维持在10%LEL(Lower Explosion Limit)以下,降低空间内油气燃爆风险。     

上海地区大气气溶胶光学厚度的遥感监测

采用V5.2算法,以MODIS 1B数据为数据源,利用Matlab软件进行数据预处理,反演了上海地区大气气溶胶光学厚度(AOD). 将AOD反演值分别与NASA的MOD04-L2气溶胶产品(10 km×10 km)以及CE-318太阳光度计实测结果进行对比. 结果表明:V5.2算法与NASA气溶胶产品相比,其精度更好,分辨率更高. 基于V5.2算法和利用MODIS遥感影像反演结果,分析了上海市典型天气AOD; 同时,将反演值与城市空气污染指数(API)进行了对比. 结果表明:AOD从一定程度上可以反映地面大气污染状况. 上海2008年AOD 12月最小,大气相对较清洁,6月最大,大气相对较浑浊;AOD的日际变化呈早晚高、中午略低的趋势,其中每日的09:00和18:00出现全天最高值,12:00左右也会出现小高峰.      

Secondary aerosol formation in winter haze over the Beijing-Tianjin-Hebei Region,China

• Characteristics and interannual variation of aerosol pollution are illustrated. • Mechanisms of secondary aerosol formation in winter haze of North China are reviewed. • Directions in future studies of secondary aerosol formation are provided. Severe haze pollution occurs frequently in the winter over the Beijing-Tianjin-Hebei (BTH) region (China), exerting profound impacts on air quality, visibility, and human health. The Chinese Government has taken strict mitigation actions since 2013 and has achieved a significant reduction in the annual mean PM_2.5 concentration over this region. However, the level of secondary aerosols during heavy haze episodes showed little decrease during this period. During heavy haze episodes, the concentrations of secondary aerosol components, including sulfate, nitrate and secondary organics, in aerosol particles increase sharply, acting as the main contributors to aerosol pollution. To achieve effective control of particle pollution in the BTH region, the precise and complete secondary aerosol formation mechanisms have been investigated, and advances have been made about the mechanisms of gas phase reaction, nucleation and heterogeneous reactions in forming secondary aerosols. This paper reviews the research progress in aerosol chemistry during haze pollution episodes in the BTH region, lays out the challenges in haze formation studies, and provides implications and directions for future research.